Air-void parameters measurement of fresh concrete and hardened concrete

Abstract

Air content, spacing factor and specific surface of fresh concrete and hardened concrete with different air contents, slumps and mineral admixtures (fly ash, slag, fly ash + slag, fly ash + slag + silica fume composite) were studied by the air-void analyzer (AVA) method and the microscopical method. The correlations between the test results obtained from different methods were analyzed. The results show that, there is a close correlation of air content and spacing factor between the fresh concrete and the hardened concrete, but the specific surface correlation is weak. The air content of concrete measured by the AVA method is smaller than that of the pressure method and the microscopical method, because AVA device captures only the air voids with the size smaller than 3 mm. Spacing factor of the fresh concrete measured by the AVA method is greater than that of the hardened concrete measured by the microscopical method, while the specific surface is smaller. When the criterion of 4%–7% air content measured by the pressure method and microscopical method is acceptable for concrete freezing-thawing (F-T) durability in cold weather, the air content measured by the AVA method should be 2.4%–4.6%. For the concrete F-T durability, when the criterion of the spacing factor measured by the microscopical method is 300 μm, the spacing factor measured by the AVA method should be 360 μm.

Keywords

fresh concrete / hardened concrete / air content / spacing factor / specific surface

References

[1] JussaraT, RicharsM. Freeze-thaw resistance of concrete with marginal air content [R]. Office of Infrastructure Research and Development Federal Highway Administration, 2006

[2] STEVE T, SEAMUS F. Evaluation of sample and testing methods for the air void analyzer [C]// 2006 Concrete Bridge Conference. Reno, USA: 111–121.

[3] FengN-q, XingFengDurability of concrete and concrete structure [M], 2009BeijingChina Machine Press303

[4] ASTM C457-2006. Standard test method for microscopical determination of parameters of the air-void system in hardened concrete [S].

[5] CLAUS Germann Petersen.. Air void analyzer (AVA) for fresh concrete: Last advances [C]. Ninth ACI International Conference on Superplasticizers and Other Chemical Admixtures in Concrete, 2009745-756

[6] LiH-jianThe durability of high-performance concrete technical measures and testing technology of high-speed railway [R], 2010BeijingChina Academy of Railway Science

[7] HuJ, HuangJ-m, LiH-jian. Study on freezing-thawing resistance and air characteristics of concrete with mineral admixtures [J]. Railway Engineering, 200918

[8] KessingerD TEvaluation of the filed application of the air voidanalyzer in quality control [D], 2010LouisvilleUniversity of Louisville

[9] DonaldD M. Evaluation of the air void analyzer [J]. Concrete Internation, 199655-59

[10] WangK-jin. Improving precision and variability of air-void analyzer (AVA) test results and developing rational specification limits [J]. National Concrete Pavement Technology Center, 200838

[11] JimGrove. Using the air void analyzer for real-time quality adjustments in the field [J]. National Concrete Pavement Technology Center, 200646-49

[12] National Concrete Pavement Technology Center.Improving variability and precision of air-void analyzer (AVA) test results and developing rational specification limits [R], 2008

[13] TP 75-08. Standard method of test for air-void characteristics of freshly mixed concrete by buoyancy change [S].

[14] OneillR CGuide to durable concrete [R], 2008Washington D C, USAACI Committee6-7

[15] ZhangS, WangK-jin. Investigation into the effect of materials and mixing procedures on air-void characteristics of fresh concrete using air-void analyzer [J]. Journal of ASTM International, 2006, 3(10): 1-15

[16] China Civil Engineering Society.Guide to durability design and construction of reinforced structures [M], 2004BeijingChina Architecture and Building Press65

[17] GB/T 50476-2008. Code for durability design on concrete structure [S].

[18] JTG/T B07-01-2006. Specification for deterioration prevention of highway concrete structures [S].

[19] TB 10005-2010. Code for durability design on concrete structure of railway [S].